1,721,011 research outputs found
Embedded Implementation of Rainflow-Counting for On-Line Predictive Maintenance
No full textPredictive maintenance can reduce unscheduled downtime and enhance the efficiency and productivity of industrial operations.Data collected on-plant is usually transmitted to local information technology (IT) systems and/or third party cloud services for storing and off-line processing, but if a reliable transmission channel is unavailable, local data processing is an attractive option.This work presents an on-line predictive maintenance system based on an embedded, real-time implementation of Miner's rule and the rainflow-counting algorithm. Memory and computing power limitations due to the use of an embedded system are taken into account, and their effects on the accuracy of the prediction are evaluated by comparing the embedded results with those of a golden standard, represented by a PC equipped with MATLAB and comparatively limitless resources. Guidelines about viable trade-offs between accuracy and computing resource requirements are extracted from simulations and experiments
Low-cost sensorless BLDC for organic fluids treatment in sterile environments
No full textThis paper presents the design and realization of a brushless DC motor-based gear pump for the treatment of organic fluids in sterile environments. Details of the FEM simulations used throughout the mechanical and electromagnetic design of the electrical machine and of the sensorless control algorithm, implemented on a motion control-oriented fixed point DSP, are reported. Construction and experimental testing of a prototype are reported as well. The realized pump features a very compact design and a fairly efficient operation. © 2008 IEEE
Sensorless SPMSM Control for Heavy Handling Machines Electrification: An Innovative Proposal
No full textThe electrification of road vehicles is a relatively mature sector, while other areas of mobility, such as construction machinery, are just beginning their transition to electric solutions. This work presents the design and realization of an integrated drive system specifically developed for retrofitting fan drives in heavy machinery, like bulldozers and tractors, utilizing existing 48 VDC batteries. By replacing or complementing internal combustion and hydraulic technologies with electric solutions, significant advantages in efficiency, reduced environmental impact, and versatility can be achieved. Focusing on the fan drive system addresses the critical challenge of thermal management in high ambient temperatures and harsh environments, particularly given the high current requirements for 3kW-class applications. A sensorless architecture has been selected to enhance reliability by eliminating mechanical position sensors. The developed fan drive has been extensively tested both on a braking bench and in real-world applications, demonstrating its effectiveness and robustness. Future work will extend this prototype to electrify additional onboard hydraulic motors in these machines, further advancing the electrification of heavy-duty equipment and improving overall efficiency and environmental impact
In-circuit Shoot-through-based Characterization of SiC MOSFET TSEP Curves for Junction Temperature Estimation
No full textJunction temperature estimation for power electronics devices is gaining more importance every day. It enables predictive maintenance and full exploitation of the power handling capability of both traditional and wide band-gap devices. The on-state voltage is known to be a good Temperature-Sensitive Electrical Parameter (TSEP), especially for MOSFETs. The main issue in its use is the need to characterize the voltage-temperature-current relationship on a per-device basis (calibration) in a controlled environment, which increases the cost for the final application.This paper presents a novel automatic calibration procedure. It builds on the innovative controlled shoot-through technique, introduced by the authors. This allows to precisely control the self-heating power of the switch and let the current flow through the device in a controlled way, even in the absence of load, provided that a half-bridge circuit is used. A specific algorithm is presented to build the voltage-temperature characteristic curve directly in-circuit and without any load connected at the bridge output. This novel technique is compared to the traditional one, relying on device characterization in a thermal chamber
Exploitation of an Industrial Low-Bandwidth Communication Line for Modulation-Level Synchronization of Voltage Source Converters
Full text linkParallelization of power electronic converter units is a way to meet the high current requirements of modern electrification applications. In case of voltage source converters, parallel operation can be attained only if the voltages of all the units are equal. In the current state of the art, this voltage synchronization can be achieved at the fundamental frequency, but not at modulation frequency, hence requiring bulky filters to limit circulating currents; this lowers the system performance in terms of cost, volume, weight and sustainability. In this paper, the authors propose a novel approach to synchronization, acting directly at the modulation frequency level, thus removing the need for any filter. This technique relies on the natural parasitic inductance and resistance of the wiring among parallel units. Specifically, this paper presents the first of two synchronization stages required to reach the sub-nanosecond synchronization necessary to completely remove the filters. At start-up, a low-bandwidth industrial communication line, based on the CAN protocol, is exploited to guarantee that the error in the synchronization of PWM signals among all the parallel units is lower than 0.1%. This limits the initial circulating current, supporting the subsequent control stage that achieves sub-nanosecond synchronization. The proposed concept is validated by experiments using a commercial MCU unit with an unadorned CAN peripheral
In-place characterization of on-state voltage for sic mosfets: Controlled shoot-through vs. film heater
Full text linkThe on-state voltage of MOSFETs is a convenient and powerful temperature-sensitive electric parameter (TSEP) to determine the junction temperature, thus enabling device monitoring, protection, diagnostics and prognostics. The main hurdle in the use of the on-state voltage as a TSEP is the per-device characterization procedure, to be carried out in a controlled environment, with high costs. In this paper, we compare two novel techniques for MOSFET junction temperature estimation: controlled shoot-through and direct heating by resistive heaters embedded in two Kapton (polyimide) films. Both allow in-place characterization of the TSEP curve with the device mounted in its final circuit and assembly, including the working heat sink. The two methods are also validated against the conventional procedure in a thermal chamber
Model-Based Optimization of a Series-Hybrid High-Performance Vehicle Powertrain with Hybrid Energy Storage System
No full textThe necessity to move towards a more sustainable mobility calls also for more efficient high-performance vehicles, which still fulfill dynamic requirements, namely, fast accelerations and limited weight. This study addresses the problem of series-hybrid powertrain mass minimization; the paper proposes sizing methodologies suitable to determine the combination of any number of primary storage systems (such as batteries and supercapacitors) that is optimal in terms of mass. The application of such methodologies indicates that it is possible to realize storage systems of about 33 kg and suitable to satisfy the power and energy requirements characterizing a representative mission profile, while achieving fuel savings in excess of 20% with respect to the ICE-only architecture
From the ideal to the real induction machine: modelling approach and experimental validation
No full textFeasibility Analysis of a More Sustainable Urban E-Vehicle: Combining Compressed Air Storage with Supercapacitor
No full textNowadays, the electric and hybrid vehicles market is wide, however these technologies are still quite elitist due to high purchase prices. Essentially, the high costs are related to battery pack and to premium magnet motors: such components require materials whose supply is questionable both from environmental and social perspectives. This study is a feasibility analysis in which compressed air, supercapacitor and switched reluctance motors are combined to realize a more sustainable vehicle powertrain that is suitable for the urban context and for short-range travels. The results show that such a powertrain is practicable in terms of mass, volume and temperature
Severity assessment of rotor faults in closed loop induction drives by different approaches
No full textIn this paper different procedures are validated to diagnose and assess the severity degree of rotor faults in closed loop controlled induction machines. The possible diagnostic indexes are investigated through spectral analysis of manipulated and controlled variables. Common control schemes have been considered to evaluate the diagnostic robustness towards operating condition and regulator parameters. Voltage injection was considered as well as a possible tool for diagnostics by analyzing the amplitude of spectral lines arising in motor input current spectrum. Experimental results guide the selection of suitable analytical models for the faulty machine. The experiments are obtained with a DSP based Current Controlled Voltage Source Inverter (CCVSI) supplying a 1.5 kW induction machine in which three different rotors differing in asymmetry degree were used. ©2007 IEEE
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